Breasts that (large or small) hang down from a woman's chest and then gradually slope outwards and up where the nipple is at the apex pointing outwards if not up. They are NOT droopy or saggy and are not flat against her body.

Any woman whose breasts start forming low on her torso and then slope out away from her body in such a way that they DO NOT point down, droop or hang can be said to have "ski-slope tits".

When you can look at a woman's profile and see that her boobs are almost to her stomach, yet they slope out from her body in such a way that she could use her nipples as headlights while walking down the road; looking ahead and not down has "ski-slope tits".